Superoxide Radical Levels Research Articles

Multimodal imaging reveals a small subpopulation of Deinococcus radiodurans exhibiting correlated low superoxide radical levels with extraordinary silver ion metabolism

AbstractA polyvalent strategy has recently been assumed to be adopted by Deinococcus radiodurans that can generate various resistance against many different detrimental sources of oxidative damage (e.g., reactive oxygen species, heavy metal ions, and ionizing radiation). On this basis, investigating more than one restorative metabolic activities and their interrelation of the very same entities of D. radiodurans is of great significance for exploring its polyextremophile nature, which will be insightful for obtaining fundamental generic insights into life sustainability. Herein, we apply mainly fluorescence microscopy and back‐reflection microscopy to visibly assess the respective activities of superoxide radical generation and silver ion metabolism for individual D. radiodurans. Strikingly, only a minority (< 20%) of the bacteria, which show low superoxide radical levels, is revealed to exhibit considerable formation of silver nanoparticles, while those containing more superoxide radicals, all show minimum silver ion metabolism. The discovery of the strong negative correlation for the small subpopulation between the two visualized different metabolic activities not only provides direct experimental evidence in terms of bacterial functionality for the inferred survival regime of the extreme microbe, but also suggests a new way of chemically examining biology from the perspective of interfunctional relationship.Keypoints The use of back‐reflection microscopy allows the discovery of a small subpopulation of Deinococcus radiodurans exhibiting extraordinary silver ion metabolism. Combining fluorescence microscopy and bright‐field microscopy, we further show the subpopulation all contain correlated relatively low levels of superoxide radicals. The findings from the angle of exploring interfunctional relationship directly support the polyvalent strategy currently proposed for the polyextremophile for survivals against various sources of oxidative damage.

Under lithium carbonate administration, nicotine triggers cell dysfunction in human glioblastoma U-251MG cells, which is distinct from cotinine.

Nicotine is an alkaloid found in tobacco leaves. Smoking prevention has been a neglected issue in psychiatry; nicotine intake in conjunction with the administration of the mood stabilizer, lithium carbonate (Li2CO3), may negatively affect brain cells. The present study investigated the combined effects of nicotine and its metabolite, cotinine, and Li2CO3 compared to acetylcholine and dopamine in U-251MG human glioblastoma cells. Cell proliferation was found to be decreased by nicotine and to be further suppressed following treatment with Li2CO3, accompanied by mitotic catastrophe and increased levels of superoxide anion radicals. By contrast, cotinine did not exert such detrimental effects. It was also found that acetylcholine did not suppress cell proliferation, whereas dopamine in conjunction with Li2CO3 decreased cell proliferation in a concentration-dependent manner. The nicotine-induced cell growth inhibition was restored by mecamylamine, a non-competitive antagonist of nicotinic acetylcholine receptors. On the whole, the findings of the present study suggest that nicotine combined with Li2CO3 leads to the suppression of the proliferation of human glioblastoma cells accompanied by mitotic catastrophe and superoxide anion radical generation. These findings may provide further cellular biological insight into the risks associated with smoking under Li2CO3 administration.

Orientin Enhances Colistin-Mediated Bacterial Lethality through Oxidative Stress Involvement.

Bacterial resistance to colistin has prompted the search for alternative strategies to enhance antibacterial potential. Combination therapy remains one of the viable strategies in antibacterial therapy and has been proven to be effective in reducing the risk of resistance. In this study, the potential of orientin for enhancing the antibacterial activity of colistin was assessed against Klebsiella pneumoniae and Pseudomonas aeruginosa in vitro. The involvement of oxidative stress in such enhancement was also assessed. The minimum inhibitory concentrations (MICs) of colistin and orientin were 16 μg/mL and 64 μg/mL against K. pneumoniae and 64 μg/mL and 256 μg/mL against P. aeruginosa respectively. For the combination therapy, orientin potentiates the antibacterial effect of colistin with a friction inhibitory concentration index (FICI) of 0.37 and 0.31 against K. pneumoniae and P. aeruginosa, respectively. This observation suggests a synergistic interaction, with the MIC of colistin being reduced by 3- and 4-fold in the presence of orientin against K. pneumoniae and P. aeruginosa, respectively. Additionally, treatment with the combination of colistin and orientin induced oxidative stress against both organisms through increased cellular levels of superoxide anion radicals with concomitant increase in NAD+/NADH and ADP/ATP ratios. These findings suggest that orientin enhanced colistin in the killing of the test bacteria and the cotreatment of colistin and orientin induced oxidative stress, through reactive oxygen species generation, which consequently facilitated bacterial lethality without causing drug-drug interactions. Although, the data presented in this study has supported the capability of orientin for strengthening antibacterial activity of colistin toward the fight against drug-resistant Gram-negative bacteria, studies focusing on the exact target and mechanism of action of orientin are underway.

Phytochemical analysis reveals an antioxidant defense response in Lonicera japonica to cadmium-induced oxidative stress

Cadmium (Cd), though potentially beneficial at lower levels to some plant species, at higher levels is a toxic metal that is detrimental to plant growth and development. Cd is also a carcinogen to humans and other contaminated plant consumers, affecting the kidneys and reducing bone strength. In this study we investigated responses of growth, chlorophyll content, reactive oxygen species levels, and antioxidant responses to Cd in honeysuckle leaves (Lonicera japonica Thunb.), a potential Cd hyperaccumulator. Results indicated that plant height, dry weight, leaf area, and chlorophyll content increased when honeysuckle was exposed to 10 mg kg−1 or 30 mg kg−1 Cd (low concentration). However, in response to 150 mg kg−1 or 200 mg kg−1 Cd (high concentration) these growth parameters and chlorophyll content significantly decreased relative to untreated control plant groups. Higher levels of superoxide radical (O2·−) and hydrogen peroxide (H2O2) were observed in high concentration Cd groups. The activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase were enhanced with exposure to increasing levels of Cd. Additionally, the Ascorbate–Glutathione (AsA–GSH) cycle was activated for the removal of H2O2 in honeysuckle in response to elevated Cd. The Pearson correlation analysis, a redundancy analysis, and a permutation test indicated that proline and APX were dominant antioxidants for removing O2·− and H2O2. The antioxidants GSH and non-protein thiols (NPTs) also increased as the concentration of Cd increased.

Epigallocatechin gallate (EGCG) restores 25-hydroxy vitamin D levels in rheumatoid arthritis patients by attenuating ROS-mediated activation of NF-κB

Purpose: To investigate the mechanism by which epigallocatechin gallate (EGCG) attenuates ROS-induced pathogenesis in a rheumatoid arthritis (RA) patients.
 Methods: Fifty patients (33 male and 17 female) aged between 25 and 60 years who satisfied ACR 1987 criteria for active RA, and thirty healthy individuals were recruited. Total peripheral blood mononuclear cells (PBMCs), neutrophils and monocytes were isolated from the blood samples of RA patients and healthy donors using commercial extraction kits. Levels of reactive oxygen species (ROS) and superoxide radical (O2-) in isolated cells were measured using fluorescence spectroscopy while the levels of the associated inflammatory cytokines (TNF-α and IL-6) were determined in PBMCs isolated from RA patients using enzyme linked immunosorbent assay (ELISA). These parameters were monitored in EGCG-treated and untreated cells. Moreover, the status of 25(OH) vitamin D and NK-κB were investigated in lipopolysaccharide (LPS)-challenged PBMCs in the presence and absence of EGCG.
 Results: Elevated levels of superoxide radical and ROS were observed in neutrophils from RA patients in the absence of ECGC, but in the presence of EGCG, the levels of the two parameters were significantly reduced (p < 0.05). Similarly, EGCG treatment downregulated the ROS-mediated increases in TNF-α and IL-6 in the PBMCs from RA patients (p < 0.05). Treatment of PBMCs with the ROS-inducing agent, LPS, resulted in the activation of NK-κB via phosphorylation, and also depletion of 25(OH) vitamin D levels (p < 0.05). However, pre-treatment of the LPS-challenged cells with EGCG inhibited NK-κB activation and 25(OH)-vitamin D depletion (p < 0.05). Moreover, 25(OH)vitamin D levels were restored in the presence of NK-κB inhibitor, flavopiridol, thereby confirming the direct regulatory role of NK-κB in 25(OH) vitamin D levels.
 Conclusion: EGCG restores 25(OH) vitamin D levels by attenuating ROS-mediated NK-κB activation. Thus, EGCG may be a promising drug candidate for RA.

Taurine modulates dynamics of oxidative defense, secondary metabolism, and nutrient relation to mitigate boron and chromium toxicity in Triticum aestivum L. plants.

The present study was undertaken to appraise the efficacy of exogenous taurine in alleviating boron (B) and chromium (Cr) toxicity. Taurine protects cell membranes from lipid peroxidation due to its function as a ROS scavenger. However, there exists no report in the literature on the role of taurine in plants under abiotic stresses. The present investigation indicated the involvement of exogenous taurine in mediating plant defense responses under B and Cr toxicity. Wheat plants manifested a significant drop in growth, chlorophyll molecules, SPAD values, relative water content, nitrate reductase activity, and uptake of essential nutrients under B, Cr, and combined B-Cr toxicity. Plants showed significant oxidative damage due to enhanced cellular levels of superoxide radicals (O2•-), hydrogen peroxide (H2O2), malondialdehyde (MDA), relative membrane permeability, and activity of lipoxygenase (LOX). Additionally, a significant negative correlation existed in B and Cr levels with the uptake of essential nutrients. Taurine substantially improved growth, photosynthetic pigments, and nutrient uptake by regulating ROS scavenging, secondary metabolism, and ions homeostasis under stress. Taurine protected plants from the detrimental effects of B and Cr by upregulating the production of nitric oxide, hydrogen sulfide, glutathione, and phenolic compounds.

Normotensive rats with PCOS exhibit the hypertensive pattern: focus on oxidative stress.

Numerous evidence implies complex interrelations between polycystic ovary syndrome (PCOS) and hypertension (HT) in reproductive-age women. In this study, we aimed to investigate the potential strain differences in ovarian morphology, hemodynamic, and biochemical characteristics in an androgen-induced PCOS rat model. A total of 24 rats of 3 weeks old (12 Wistar Kyoto - WK and 12 spontaneously hypertensive rats - SHR) were divided into four groups: WK, WK PCOS, SHR, and SHR PCOS. PCOS was induced by daily s.c. injections of testosterone enanthate (1 mg/100 g body weight) administered for 5 weeks. PCOS induction led to estrus cyclicity cessation, cystic ovarian appearance, and sex hormones disturbances in both strains. The morphometric parameters in ovaries were altered in a manner of PCOS-related changes in both strains (higher number in preantral, atretic, and cystic follicles). Ultrasonographically, a significant decrease in ovarian volume (OV) was registered in PCOS groups but also in SHR compared to WK rats. All blood pressure parameters were higher in SHR compared to WK. PCOS modeling increased systolic, mean arterial, and pulse pressure in WK strain, while in SHR, only mean arterial and pulse pressure were higher. Alterations in oxidative stress parameters could provide a molecular basis for PCOS-related changes: in PCOS groups, thiobarbituric acid reactive substance and superoxide anion radical levels were higher in both strains, while superoxide dismutase and glutathione were significantly lowered.

Deletion of rifampicin-inactivating mono-ADP-ribosyl transferase gene of Mycobacterium smegmatis globally altered gene expression profile that favoured increase in ROS levels and thereby antibiotic resister generation.

The physiological role of mono-ADP-ribosyl transferase (Arr) of Mycobacterium smegmatis, which inactivates rifampicin, remains unclear. An earlier study reported increased expression of arr during oxidative stress and DNA damage. This suggested a role for Arr in the oxidative status of the cell and its associated effect on DNA damage. Since reactive oxygen species (ROS) influence oxidative status, we investigated whether Arr affected ROS levels in M. smegmatis. Significantly elevated levels of superoxide and hydroxyl radical were found in the mid-log phase (MLP) cultures of the arr knockout strain (arr-KO) as compared those in the wild-type strain (WT). Complementation of arr-KO with expression from genomically integrated arr under its native promoter restored the levels of ROS equivalent to that in WT. Due to the inherently high ROS levels in the actively growing arr-KO, rifampicin resisters with rpoB mutations could be selected at 0 hr of exposure itself against rifampicin, unlike in the WT where the resisters emerged at 12th hr of rifampicin exposure. Microarray analysis of the actively growing cultures of arr-KO revealed significantly high levels of expression of genes from succinate dehydrogenase I and NADH dehydrogenase I operons, which would have contributed to the increased superoxide levels. In parallel, expression of specific DNA repair genes was significantly decreased, favouring retention of the mutations inflicted by the ROS. Expression of several metabolic pathway genes also was significantly altered. These observations revealed that Arr was required for maintaining a gene expression profile that would provide optimum levels of ROS and DNA repair system in the actively growing M. smegmatis.

Biochar and Chitosan Regulate Antioxidant Defense and Methylglyoxal Detoxification Systems and Enhance Salt Tolerance in Jute (Corchorus olitorius L.).

We investigated the role of biochar and chitosan in mitigating salt stress in jute (Corchorus olitorius L. cv. O-9897) by exposing twenty-day-old seedlings to three doses of salt (50, 100, and 150 mM NaCl). Biochar was pre-mixed with the soil at 2.0 g kg−1 soil, and chitosan-100 was applied through irrigation at 100 mg L−1. Exposure to salt stress notably increased lipid peroxidation, hydrogen peroxide content, superoxide radical levels, electrolyte leakage, lipoxygenase activity, and methylglyoxal content, indicating oxidative damage in the jute plants. Consequently, the salt-stressed plants showed reduced growth, biomass accumulation, and disrupted water balance. A profound increase in proline content was observed in response to salt stress. Biochar and chitosan supplementation significantly mitigated the deleterious effects of salt stress in jute by stimulating both non-enzymatic (e.g., ascorbate and glutathione) and enzymatic (e.g., ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase, glutathione reductase superoxide dismutase, catalase, peroxidase, glutathione S-transferase, glutathione peroxidase) antioxidant systems and enhancing glyoxalase enzyme activities (glyoxalase I and glyoxalase II) to ameliorate reactive oxygen species damage and methylglyoxal toxicity, respectively. Biochar and chitosan supplementation increased oxidative stress tolerance and improved the growth and physiology of salt-affected jute plants, while also significantly reducing Na+ accumulation and ionic toxicity and decreasing the Na+/K+ ratio. These findings support a protective role of biochar and chitosan against salt-induced damage in jute plants.

The Short-Term Exposure to SDHI Fungicides Boscalid and Bixafen Induces a Mitochondrial Dysfunction in Selective Human Cell Lines.

Fungicides are used to suppress the growth of fungi for crop protection. The most widely used fungicides are succinate dehydrogenase inhibitors (SDHIs) that act by blocking succinate dehydrogenase, the complex II of the mitochondrial electron transport chain. As recent reports suggested that SDHI-fungicides could not be selective for their fungi targets, we tested the mitochondrial function of human cells (Peripheral Blood Mononuclear Cells or PBMCs, HepG2 liver cells, and BJ-fibroblasts) after exposure for a short time to Boscalid and Bixafen, the two most used SDHIs. Electron Paramagnetic Resonance (EPR) spectroscopy was used to assess the oxygen consumption rate (OCR) and the level of mitochondrial superoxide radical. The OCR was significantly decreased in the three cell lines after exposure to both SDHIs. The level of mitochondrial superoxide increased in HepG2 after Boscalid and Bixafen exposure. In BJ-fibroblasts, mitochondrial superoxide was increased after Bixafen exposure, but not after Boscalid. No significant increase in mitochondrial superoxide was observed in PBMCs. Flow cytometry revealed an increase in the number of early apoptotic cells in HepG2 exposed to both SDHIs, but not in PBMCs and BJ-fibroblasts, results consistent with the high level of mitochondrial superoxide found in HepG2 cells after exposure. In conclusion, short-term exposure to Boscalid and Bixafen induces a mitochondrial dysfunction in human cells.

Insulin signaling alters antioxidant capacity in the diabetic heart

Diabetic cardiomyopathy is associated with an increase in oxidative stress. However, antioxidant therapy has shown a limited capacity to mitigate disease pathology. The molecular mechanisms responsible for the modulation of reactive oxygen species (ROS) production and clearance must be better defined. The objective of this study was to determine how insulin affects superoxide radical (O2•–) levels. O2•– production was evaluated in adult cardiomyocytes isolated from control and Akita (type 1 diabetic) mice by spin-trapping electron paramagnetic resonance spectroscopy. We found that the basal rates of O2•– production were comparable in control and Akita cardiomyocytes. However, culturing cardiomyocytes without insulin resulted in a significant increase in O2•– production only in the Akita group. In contrast, O2•– production was unaffected by high glucose and/or fatty acid supplementation. The increase in O2•– was due in part to a decrease in superoxide dismutase (SOD) activity. The PI3K inhibitor, LY294002, decreased Akita SOD activity when insulin was present, indicating that the modulation of antioxidant activity is through insulin signaling. The effect of insulin on mitochondrial O2•– production was evaluated in Akita mice that underwent a 1-week treatment of insulin. Mitochondria isolated from insulin-treated Akita mice produced less O2•– than vehicle-treated diabetic mice. Quantitative proteomics was performed on whole heart homogenates to determine how insulin affects antioxidant protein expression. Of 29 antioxidant enzymes quantified, thioredoxin 1 was the only one that was significantly enhanced by insulin treatment. In vitro analysis of thioredoxin 1 revealed a previously undescribed capacity of the enzyme to directly scavenge O2•–. These findings demonstrate that insulin has a role in mitigating cardiac oxidative stress in diabetes via regulation of endogenous antioxidant activity.

Synergistic action of silicon nanoparticles and indole acetic acid in alleviation of chromium (CrVI) toxicity in Oryza sativa seedlings

The present study investigates ameliorative effect of silicon nanoparticles (SiNPs) and indole acetic acid (IAA) alone and in combination against hexavalent chromium (CrVI) toxicity in rice seedlings. The results of the study revealed protective effects of SiNPs and IAA against CrVI toxicity. The 100 μM of CrVI imposed toxic effects in rice seedlings at morphological, physiological and biochemical levels which coincided with increased level of intracellular CrVI and declined level of endogenous nitric oxide (NO). The CrVI enhanced levels of superoxide radicals (SOR) (59.51% and 50.1% in shoot and root, respectively) and H2O2 (19.5% and 23.69% in shoot and root, respectively). However, when SiNPs and IAA were applied to plants under CrVI stress, they enhanced tolerance and defence mechanisms as manifested in terms of increased biomass, endogenous NO, photosynthetic pigments, and antioxidants level. It was also noticed that CrVI arrested cell cycle at G2/M phase whereas growth was restored as compared to control when SiNPs and IAA were supplemented. Thus, the hypothesis that combined application of SiNPs and IAA will be effective in alleviating CrVI toxicity is validated from the results of this study. Moreover, in SiNPs and IAA-mediated mitigation of CrVI toxicity, endogenous NO has a positive role. The importance of the study will be that the combination of SiNPs and IAA can be utilized against heavy metal stress and even when supplied alone, they will enhance the crop productivity parameters with and without stress conditions.

Neuroprotective Effects of Delta-9-Tetrahydrocannabinol against FeSO4- and H2O2-Induced Cell Damage on Dopaminergic Neurons in Primary Mesencephalic Cell Culture

AbstractDelta-9-Tetrahydrocannabinol and other phytocannabinoids have been previously demonstrated to possess neuroprotective effects in murine mesencephalic cell culture models of Parkinson’s disease, in which increased levels of superoxide radicals led to the loss of dopaminergic neurons. In these models, delta-9-tetrahydrocannabinol did not scavenge these radicals but displayed antioxidative capacity by increasing glutathione levels. Based on these findings, in the present study, we investigated whether the neuroprotective effect of delta-9-tetrahydrocannabinol can also be detected in FeSO4- and H2O2-stressed cells. Mesencephalic cultures were concomitantly treated with FeSO4 (350 μM) or H2O2 (150 μM) and delta-9-tetrahydrocannabinol (0.01, 0.1, 1, 10 μM) on the 12th days in vitro for 48 h. On the 14th DIV, dopaminergic neurons were stained immunocytochemically by tyrosine hydroxylase, and fluorescently using crystal violet, Hoechst 33342, and JC-1. FeSO4 and H2O2 significantly reduced the number of dopaminergic neurons by 33 and 36%, respectively, and adversely affected the morphology of surviving neurons. Moreover, FeSO4, but not H2O2, significantly decreased the fluorescence intensity of crystal violet and Hoechst 33342, and reduced the red/green ratio of JC-1. Co-treatment with delta-9-tetrahydrocannabinol at the concentrations 0.01 and 0.1 μM significantly rescued dopaminergic neurons in FeSO4 and H2O2-treated cultures by 16 and 30%, respectively. delta-9-Tetrahydrocannabinol treatment also led to a higher fluorescence intensity of crystal violet and Hoechst 33342, and increased the red/green fluorescence ratio of JC-1 when concomitantly administered with FeSO4 but not H2O2. To conclude, delta-9-tetrahydrocannabinol rescues dopaminergic neurons against FeSO4- and H2O2-induced neurotoxicity. Using fluorescence dyes, this effect seems to be mediated partially by restoring mitochondrial integrity and decreasing cell death, particularly in FeSO4-treated cultures.

Response of platelets to silver nanoparticles designed with different surface functionalization

Despite increasing use of silver nanoparticles (AgNPs) in different medicinal products, knowledge about their effects on hemostasis and platelets functionality is still scarce. Published scientific reports provide neither data on oxidative stress response of platelets to AgNPs nor information about the effects of AgNPs physicochemical properties on functionality and activation of platelets. This study aimed to explore the role of AgNPs surface functionalization on cell viability, particle uptake, oxidative stress response, and activation of platelets. Small sized, spherical AgNPs were surface functionalized by negatively charged sodium bis(2-ethylhexyl) sulphosuccinate (AOT), neutral polymer polyvinylpyrrolidone (PVP), positively charged polymer poly-l-lysine (PLL) and bovine serum albumin (BSA). Platelet viability, activation and particle uptake were evaluated by flow cytometry. Oxidative stress response was evaluated by measuring the levels of intracellular glutathione (GSH), peroxy and superoxide radicals using assays based on fluorescence dies. Cytotoxicity and uptake of AgNPs to platelets were found to be dose-dependent in a following order PLL-AgNP >> > BSA-AgNP > AOT-AgNP > PVP-AgNP. Particle internalization was further confirmed by transmission electron microscopy. Treatment of platelets with AgNPs induced superoxide radical formation, depletion of GSH and hyperpolarization of the mitochondrial membrane. Small, but statistically significant increase of P-selectin expression in cells treated with all AgNPs compared to non-treated controls evidenced AgNPs-induced activation of platelets. Increased PAC-1 expression was found only in platelets treated with PLL-AgNPs. Obtained results demonstrate that different surface decoration of AgNPs determines their biological effects on platelets highlighting the importance of careful design of AgNPs-based medicinal products regarding their biocompatibility and functionality.

Standardized Aronia melanocarpa extract regulates redox status in patients receiving hemodialysis with anemia

The aim of our study was to investigate the effects of one-month consumption of polyphenol-rich standardized Aronia melanocarpa extract (SAE) on redox status in anemic hemodialysis patients. The study included 30 patients (Hb < 110g/l, hemodialysis or hemodiafiltration > 3months; > 3 times week). Patients were treated with commercially available SAE in a dose of 30ml/day, for 30days. After finishing the treatment blood samples were taken to evaluate the effects of SAE on redox status. Several parameters of anemia and inflammation were also followed. After the completion of the treatment, the levels of superoxide anion radical and nitrites significantly dropped, while the antioxidant capacity improved via elevation of catalase and reduced glutathione. Proven antioxidant effect was followed by beneficial effects on anemia parameters (increased hemoglobin and haptoglobin concentration, decreased ferritin and lactate dehydrogenase concentration), but SAE consumption didn't improve inflammatory status, except for minor decrease in C-reactive protein. The consumption of SAE regulates redox status (reduce the productions of pro-oxidative molecules and increase antioxidant defense) and has beneficial effects on anemia parameters. SAE could be considered as supportive therapy in patients receiving hemodialysis which are prone to oxidative stress caused by both chronic kidney disease and hemodialysis procedure. Additionally, it could potentially be a good choice for supplementation of anemic hemodialysis patients. TRN: NCT04208451 December 23, 2019 "retrospectively registered".

Magneto-mechanical effects of magnetite nanoparticles on Walker-256 carcinosarcoma heterogeneity, redox state and growth modulated by an inhomogeneous stationary magnetic field

Iron oxide (Fe3O4) magnetic nanoparticles (MNs) delivered to the tumor under the influence of magnetic fields can generate reactive oxygen species (ROS) that affect the activity of mitochondrial enzymes, DNA damage and abnormal cell growth. Previous investigations used rotating magnetic fields to inhibit tumor growth. Herein, we question whether the magneto-mechanical effects of MNs under an inhomogeneous stationary magnetic field (ISMF) can modulate tumor heterogeneity, ROS and growth. Animals with Walker-256 carcinosarcoma in group 1 underwent no treatment (control), group 2 received MNs, while group 3 was treated with MNs + ISMF. MNs were injected with tumor cells. ISMF treatment was given every other day starting 2 days after implantation. MNs + ISMF showed a 51% increase in the tumor growth factor compared with MNs alone. Elevated levels of free iron and superoxide radical as well as decreased lactoferrin and NO-FeS-proteins were measured after MNs + ISMF treatment. The present study provides experimental evidence that the magnetic force exerted by ISMF upon MNs initiates morphological heterogeneity, modulates ROS generation and promotes tumor growth. Therefore, these findings propose to circumvent the negative effects of MNs by a shortened duration of targeted delivery, application of slowly changing ISMFs, and combination of ISMFs with alternating magnetic fields to modulate iron-dependent redox reactions.

Salicylic acid pre-treatment modulates Pb2+-induced DNA damage vis-à-vis oxidative stress in Allium cepa roots.

The current study investigated the putative role of salicylic acid (SA) in modulating Pb2+-induced DNA and oxidative damage in Allium cepa roots. Pb2+ exposure enhanced free radical generation and reduced DNA integrity and antioxidant machinery after 24 h; however, SA pre-treatment (for 24 h) ameliorated Pb2+ toxicity. Pb2+ exposure led to an increase in malondialdehyde (MDA) and hydrogen peroxide (H2O2) accumulation and enhanced superoxide radical and hydroxyl radical levels. SA improved the efficiency of enzymatic antioxidants (ascorbate and guaiacol peroxidases [APX, GPX], superoxide dismutases [SOD], and catalases [CAT]) at 50-μM Pb2+concentration. However, SA pre-treatment could not improve the efficiency of CAT and APX at 500 μM of Pb2+ treatment. Elevated levels of ascorbate and glutathione were observed in A. cepa roots pre-treated with SA and exposed to 50 μM Pb2+ treatment, except for oxidized glutathione. Nuclear membrane integrity test demonstrated the ameliorating effect of SA by reducing the number of dark blue-stained nuclei as compared to Pb2+ alone treatments. SA was successful in reducing DNA damage in cell exposed to higher concentration of Pb2+ (500 μM) as observed through comet assay. The study concludes that SA played a major role in enhancing defense mechanism and protecting against DNA damage by acclimatizing the plant to Pb2+-induced toxicity.

GC-MS screening and antiparasitic action of Putranjiva roxburghii leaves against sensitive and resistant strains of Leishmania donovani.

Looming drug resistance cases of leishmaniasis infection are an undeniably serious danger to worldwide public health, also jeopardize the efficacy of available drugs. Besides this, no successful vaccine is available till date. Since the ancient era, many plants and their parts have been used as medicines against various ailments. Hence, the importance of drug development for new molecules against Leishmania infection is significant that is a cost-effective and safer drug preferably from the natural herbal resources. We evaluated the GC-MS screening and efficacy of Putranjiva roxburghii (PR) against the sensitive and resistant promastigotes of L. donovani. GC-MS profiling revealed that the extract was rich in myo-inositol-4-C-methyl, azulene and desulphosinigrin. Quantitative investigation of phytoconstituents confirmed that PR was rich in phenols, flavonoids and terpenoids. We found an IC50 25.61 ± 0.57µg/mL and 29.02 ± 1.21µg/mL of PR against sodium stibogluconate sensitive and resistant strain respectively. It was found to be safer in cytotoxicity assay and generated ROS mediated oxidative stress in the parasitic cells which was evidenced by the increased and decreased levels of superoxide radicals, lipid peroxidation products, lipid bodies and levels of thiol, plasma membrane integrity respectively. Therefore, our results support the importance of P. roxburghii as a medicinal plant against L. donovani and showed potential for exploration as an antileishmanial agent.

Comparison of Oxidant Stress Levels among Healthy, Chronic Periodontitis, and Ischemic Heart Disease Subjects with Presence or Absence of Chronic Periodontitis.

Objective:To investigate the total oxidant levels in healthy, chronic periodontitis (CP), and ischemic heart disease (IHD) and to check for any correlation among them.Materials and Methods:A sample of 80 were split into four groups of healthy subjects (Group I), CP subjects (Group II), IHD subjects (Group III), and IHD subjects having periodontitis (Group IV). The serum and saliva samples collected were analyzed for levels of hydrogen peroxide (H2O2), hydroxyl radical (OH-), nitric oxide (NO), and superoxide radical (O2-).Results:There were significant (P < 0.05) variances in the mean serum and salivary levels of hydrogen peroxide, hydroxyl radical, NO, and superoxide within the 4 groups. Oxidant levels of both serum and saliva were lower in disease groups of Group II, III, and IV as compared to healthy controls, with different patterns.Conclusion:The oxidant levels (H2O2, OH-, NO, and O2-) are significantly hampered in periodontitis and IHD subjects as compared to healthy subjects. The oxidants, whether serum or salivary, did not always show the proportional change as a result of change in oxidant stress due to disease as positive correlation was observed only in the serum H2O2 and salivary NO radical levels and between serum superoxide dismutase radical and salivary H2O2 in Group I. In Group III, there was a positive correlation between serum NO radical and salivary H2O2.

Antioxidant Adjustments of Olive Trees (Olea Europaea) under Field Stress Conditions.

Extreme climate events are increasingly frequent, and the 2017 summer was particularly critical in the Mediterranean region. Olive is one of the most important species of this region, and these climatic events represent a threat to this culture. However, it remains unclear how olive trees adjust the antioxidant enzymatic system and modulate the metabolite profile under field stress conditions. Leaves from two distinct adjacent areas of an olive orchard, one dry and the other hydrated, were harvested. Tree water status, oxidative stress, antioxidant enzymes, and phenolic and lipophilic metabolite profiles were analyzed. The environmental conditions of the 2017 summer caused a water deficit in olive trees of the dry area, and this low leaf water availability was correlated with the reduction of long-chain alkanes and fatty acids. Hydrogen peroxide (H2O2) and superoxide radical (O2•–) levels increased in the trees collected from the dry area, but lipid peroxidation did not augment. The antioxidant response was predominantly marked by guaiacol peroxidase (GPOX) activity that regulates the H2O2 harmful effect and by the action of flavonoids (luteolin-7-O-glucuronide) that may act as reactive oxygen species scavengers. Secoiridoids adjustments may also contribute to stress regulation. This work highlights for the first time the protective role of some metabolite in olive trees under field drought conditions.